Controls Window

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Application Window	Message Window	Graphics Window	Access Window	Explorer Window	Trend Window	Controls Window	TagList Window	Project Window

Latest SysCAD Version: 19 March 2024 - SysCAD 9.3 Build 139.35102

Related Links: Control Commands, Controls

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Introduction

The main functions of this Controls Window are to list all the PID controllers used in the project for analysis, trending and tuning. It is The Controls window is saved with extension trc. From Build 139, this file is saved to the \DocsTrend subfolder.

When a new Controls page is created, all PID controllers used in the project will be added to this Controls window automatically. From Build 139.31866, the list of PIDs is automatically sorted and updated as PIDs are added, deleted or renamed. In older Builds, this needs to be done manually by using the Trend | Reconnect all option.

Open a New Controls Window

To open a new Controls window, use one of the following commands:

• If the 'Control' menu is active (click on any Controls window), click on Control - New Control Window.
• Right click on 'Trends' in the Explorer Window (if this is not already open, click on View - Explorer) and select 'New Controls Window'.
• With a project open, use one of the following commands:

Window - New Document Icon: Short Cut Key: Ctrl+N Select the 'Controls' option, and press 'OK'. Each of these methods will open a new Controls Window 'Controls_x.trc.' Notes: This command is only available if a SysCAD project is open. This command is not available if SysCAD is solving or running.

The Tuning Parameters

The controls window is basically divided into three sections, the first and third sections are the same as the normal trend window, being the Trend Line View and Trend List View respectively. See Trend Window (Normal). The second section is unique to the controls window, listing all the necessary tuning parameters for the controllers.

An example of the Controls window is shown below:

Notes on Autotune:

1. Only one PID loop can be auto tuned at any one time. The user may then repeat the exercise to tune other controllers in the project.
2. As with any operating plants, some controllers may need more fine tuning depending on the interaction with other controllers. In most cases, it is best to hand-tune some of the more sensitive controllers first to get the plant under control and use the auto tune for optimisation.

Tuning Options	AutoTune  : This turns on the Auto Tune function where SysCAD analyses the behaviour of the control loop in view using the user specified/default settings and optimises the PID. When the controller is tuned, it overwrites the user specified Gain, PB, Ic and Dc values with the optimum values derived from the tuning exercise. TuneWithHold : This allows the user to tune a loop while holding other loops steady, only works in conjunction with AutoTune. HoldAll : Holds all control loops steady.
Plant Value	Plant Gain : The total gain Plant Delay Plant Period
Turning PID Values and Tuning Parameters	PID Gain : This is the gain for the PID loop in view, denoted by the blue magnifying glass icon . PID Integral (Ic) : This is the integral for the PID loop in view, denoted by the blue magnifying glass icon . PID Derivative (Dc) : This is the derivative for the PID loop in view, denoted by the blue magnifying glass icon . Min Settle Count : The minimum number of iterations used to test for loop steadiness. Max Settle Count : The maximum number of iterations used to test for loop steadiness. TestDelta : This is the step size used while analysing the behaviour of the loop. Eg, 0.01 is 1% change of output value. MaxPBDeRate : This is the factor used to change the value of the PB while Auto Tuning.
Turning triggers and status display	Clicking on under State enables the user to view the tuning parameters for the selected loop. Only one PID loop's parameters can be viewed at a time. (See parameters PID gain, Ic, Dc above.) Clicking on under State toggles the loop's output to be auto/manual. Colour code: green - auto; yellow - manual; red - all controller for the PID unit are switched off, not present or controller is switched off individually. The symbol will appear under State when the loop is on hold. Clicking on under State toggles the loop's tune option on/off. The symbols & will appear under State when the loop is being auto-tuned.
Trending	The set point (value), measured (process variable value) and output (value) can be trended. e.g.:

How to Auto Tune a Single Loop

1. Add a Controls Window if the project doesn't already have one. (One per project only.)
2. Enable the AutoTune option which is located at in the top left corner of the Controls Window
3. Make sure all PID controllers have the TuneWithHold option selected
4. If the controller to be tuned is currently converged, force it to change output by either introducing a disturbance/step change to a variable which will affect its measured value or simply change the controller's setpoint
5. For the PID controller to be tuned, left click on the relevant under the State heading , if the is not present, right click under the State Heading next to the PID of interest and choose Tune.
6. Solve or Run the project , this will start the PID tuning
7. All the other controller's outputs will be held constant while the controller is being tuned, shown by the symbol
8. While the controller is being tuned, the & symbols will be shown next to it and the controller output will be held constant
9. When the tuning has been completed, the controller settings (Gain, Integral, Derivative) will be changed to new values and all controllers will be allowed to control normally